The Study of Two Models for Power Transformer Winding Deformation

Transformer, one of the most important components in a power system, functions as the vital to the safety of power supply system. However, great economic losses and industrial accidents can result from transformer winding deformation. Therefore, it is quite essential to use a precise transformer model when taking simulation to diagnose the transformer winding deformation correctly and instantly. And many studies show that there are two models of transformer winding used mostly and performing well in the simulation of transformers with the fault. One is equivalent circuit model, and the other is multi-conductor transmission line model. To tell the difference of these two models, we performed the study on power transformer SFSZ11-180000/220 and SF11-31500/35 and got the frequency response curves from the equivalent circuit models using inter-turn and inter-disc parameters and multiconductor transmission line model. And the conclusions are that both equivalent circuit model and multi-conductor transmission line model can reflect the degree of bulge deformation. However, multi-conductor transmission line model can reflect the degree of bulge deformation in wider frequency range. In addition, it will cause the difference of frequency curves whether the parameters used in models are inter-turn or inter-disc for equivalent circuit model multi-conductor transmission line model.